Braking device for feeding means of pilgering mills



J. 'GASSEE BRAKING DEVICE FOR FEEDING MEANS OF PILGERING MILLS Filed July 31, 1954 Patented Feb. 25, 1936 UNITED STATES PATENT OFFICE BRAKING DEVICE FOR FEEDING MEANS OF PILGERING MILLS many Application July 31, 1934, Serial No. 737,726 In Great Britain August 3, 1933 3 Claims.

My invention relates to braking devices for feeding means of pilgering mills.

In the rolling of tubes on pilgering mills, a tube blank carried on a mandrel is fed rapidly forward to the pilgering rolls after each revolution of the rolls. In order to protect the parts of the mill against heavy shocks and breakage, braking devices are usually associated with said feeding means.

A braking device suitable for that purpose is for instance disclosed in Patent 1,833,990 to Hans Dreyer in which a liquid is compressed on each forward stroke of the feeding means which liquid in its turn compresses a mass of air enclosed in a vessel. The compression of the enclosed air results in braking the feeding means and the parts moving together with it.

Now, for obtaining a high output from a mill in a given time, it is necessary to have a high feeding speed of the blank. The higher the speed, the more powerful, on the other hand, the braking force required for stopping the rapidly moving masses. With the old arrangements, an increase of the braking force was only possible in a manner which considerably reduced the speed of the feeding means all over the forward travel so that nothing was gained on the whole by the increased speed.

It is an object of my invention to provide a braking device for feeding means of pilgering mills of the type disclosed in the aforementioned patent by which powerful braking can be obtained without the speed of the feeding stroke being materially impaired.

A further drawback of known braking devices is that, in the course of their operation, the air is highly heated by its continual compression. Since the pressure of the air is also influenced by its temperature, it is obvious, that the braking effect exerted on the feeding means will vary with the number of strokes. A uniform braking effect is, however, very desirable.

It is, therefore, a further object of my invention to provide means by which a uniform braking effect will be secured.

In the drawing, I have shown a preferred embodiment of my invention, the only figure being a longitudinal section through the feeding means of a pilgering mill which is equipped with my novel braking device.

I are the rolls of a pilgering mill of known shape which work on a tube blank 2 carried by a mandrel 3. The latter is rigidly connected by a coupling box I3 to feeding means which comprise a rod 4 and a piston 5 adapted to reciprocate in a cylinder 6. The latter is filled with a fluid under pressure which drives the piston 5 and the parts connected thereto forward towards the pilgering rolls I when the latter are not working the blank 2 and pushing it back against the pressure of the fluid.

Cylinder 6 is supported by a bed plate 9 which also carries a second cylinder 1 forming a part of the braking device. Rod 4 extends through the cylinder I and has a shoulder I4 which acts as a plunger on a suitable liquid I5 contained in cylinder I when the rod 4 is reciprocated. An abutment ring 8 for the plunger I4 is provided at the outer end of cylinder I. Attached to cylinder 1, and projecting above it, is an air vessel I6 in free communication with the cylinder I.

According to the present invention, vessel I6 is of cylindrical shape formed with an upwardly tapered portion. As the plunger I4 advances on its forward stroke when the tube blank 2 is fed to the pilgering rolls I, the liquid I5 is forced more and more into the vessel I6 thereby compressing the air enclosed in that vessel which brings about a braking effect on plunger I4 and the feeding means. Because of the preferred form of the vessel I6, that compression is much more intense at the end of the feeding stroke than at its beginning so that all the required braking effect can be obtained during the last part of the feeding stroke, while the speed of the feeding means during the first part is left substantially unimpaired.

In order to adjust the braking effect to different conditions, a shut-off valve I2 is provided at the upper end of vessel I6 for the liquid I5 to be introduced or withdrawn.

Furthermore, the vessel I6 is provided with a cooling means by which the heat developed in the air is absorbed so that its temperature will be maintained even throughout the whole time of operation. To this end, I surround vessel IS with a jacket I0 filled with a cooling medium I I which may be water, oil, gas or simply air. The medium is admitted and discharged at different levels by pipes shown in the drawing.

I claim:

1. In a braking device for the feeding means of pilgering mills, the combination with a cylinder filled with a liquid and a braking plunger adapted to reciprocate in said cylinder and operatively connected with the feeding means, of a closed air-filled vessel in direct communication with said cylinder having a constricted upper portion so disposed as to offer a rapidly increasing powerful resistance to the liquid displaced 5 2032,27? 7' 7 by said plunger toward the end of the feeding operatirely connected with said feeding means'mf stroke. 1 I Z r V n a closed air-filled vessel in direct communication 7 2. The combination as specified in claim 1, inwith said cylinder, beingof substantially cylincluding a cooling jacket surrounding the condrical shape and terminating in a bottle-neck stricted upper portion of said vessel. upper portion offering a rapidly increasing power- 5 V 3. In a braking device for the feeding means ful resistance to the liquid displaced "by said of pilgering mills the combination with a cylplunger toward the end of the feeding stroke, inder filled with a liquid and a. braking plunger. i mounted for reciprocation in said cylinder and JGSEF GASSEN. 

